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Molecular mechanism of positive allosteric modulation of the metabotropic glutamate receptor 2 by JNJ-46281222
Background and Purpose
Allosteric modulation of the mGlu2 receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [3H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode.
Experimental Approach
We have used radioligand binding studies, functional assays, site-directed mutagenesis,...
Show moreBackground and Purpose
Allosteric modulation of the mGlu2 receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [3H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode.
Experimental Approach
We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222.
Key Results
JNJ-46281222 is an mGlu2-selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [3H]-JNJ-46281222 was increased by the presence of glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [3H]-JNJ-46281222 binding experiments on mutant receptors.
Conclusion and Implications
Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C receptor drug discovery.
Show less- All authors
- Doornbos, M.L.J.; Perez-Benito, L.; Tresadern, G.; Mulder, T.; Biesmans, I.; Trabanco, A.A.; Cid, M.J.; Lavreysen, H.; IJzerman, A.P.; Heitman, L.H.
- Date
- 2016-02-28
- Volume
- 173
- Issue
- 3
- Pages
- 588 - 600